The regional councillor for infrastructure, Renato Chisso, was also arrested on Wednesday morning as part of the investigation into alleged misuse of public funds relating to Moses, a project to safeguard Venice from flooding, Il Messaggero reported.
Their arrests follow the arrests last year of Piergiorgio Baita, the former CEO of the construction group, Mantovani, and Giovanni Mazzacurati, the chief engineer of the Moses project, the newspaper said.
Orsoni's lawyers said in a statement that the allegations "appear hardly credible" and said the accusations were coming from people who were already under investigation.
Venice’s prosecutor has also called for the arrest of Giancarlo Galan, Veneto’s ex-president and a current senator as well as European Parliament member Lia Sartori – both from former prime minister Silvio Berlusconi's Forza Italia (Go Italy) party.
Galan led Venice between 1995 and 2010 and was also agriculture minister in Berlusconi's government.
Thirty-five people have so far been arrested over alleged embezzlement relating to the project, which got underway over 10 years ago and has involved the construction of barriers to protect Venice from flooding.
Among the others arrested are Giampiero Marchese, the regional councillor for the Democratic party, businessmen Franco Morbiolo and Roberto Meneguzzo, and a retired police general, Emilio Spaziante.
The flurry of arrests comes three years after the probe was launched by the Finance Police.
The police said they had traced some €20 million in kickbacks from contractors for the project that were transferred into foreign bank accounts allegedly used for political party
"Most of these funds were used for financing political parties on a local, regional and national level," chief prosecutor Luigi Delpino said at a press conference.
It is alleged that Baita, the ex-CEO of Mantovani, with the help of CFO Nicolò Buson, diverted money into a number of accounts overseas, TGCOM24 reported.
The money was allegedly taken to San Marino, a tax haven on Italy’s mainland, by the former secretary of Galan, where it was laundered by William Colombelli through his finance company, BMC.
The Moses project, launched by Galan and Berlusconi, in 2003 and has cost some €5.4 billion. It was scheduled for completion this year but has been repeatedly hit by delays.
The operation involves around 50 subcontractors working on more than 20 kilometres of the Venice lagoon to build 78 mobile barriers against high tides and flooding.
The scandal is the latest surrounding a major public works project in Italy, following similar investigations into building for Milan Expo 2015, post-quake reconstruction in L'Aquila and preparations for the G8 summit in 2009.
"The way we handle public works in this country generates bribes. Everything is concentrated in the hands of very few entities and people to move fast," Massimo Cacciari, a former mayor of Venice, told news channel SkyTG24.
Venice is badly in need of protection due to yearly flooding known as "acqua alta" (high water) – due to a combination of tides, currents and strong winds.
The city sank 23 centimetres during the whole of the 20th century and is increasingly vulnerable as sea levels rise.